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A264983 Odd bisection of A263273. 4

%I #10 May 22 2017 20:07:36

%S 1,3,7,5,9,19,13,21,25,11,15,23,17,27,55,37,57,73,31,39,67,49,63,61,

%T 43,75,79,29,33,65,47,45,59,41,69,77,35,51,71,53,81,163,109,165,217,

%U 91,111,199,145,171,181,127,219,235,85,93,193,139,117,175,121,201,229,103,147,211

%N Odd bisection of A263273.

%H Indranil Ghosh, <a href="/A264983/b264983.txt">Table of n, a(n) for n = 0..10000</a>

%F a(n) = A263273(2n + 1).

%t f[n_] := Block[{g, h}, g[x_] := x/3^IntegerExponent[x, 3]; h[x_] := x/g@ x; If[n == 0, 0, FromDigits[Reverse@ IntegerDigits[#, 3], 3] &@ g[n] h[n]]]; t = Select[f /@ Range@ 130, OddQ] (* _Michael De Vlieger_, Jan 04 2016, after _Jean-François Alcover_ at A263273 *)

%o (Scheme) (define (A264983 n) (A263273 (+ 1 n n)))

%o (Python)

%o from sympy import factorint

%o from sympy.ntheory.factor_ import digits

%o from operator import mul

%o def a030102(n): return 0 if n==0 else int(''.join(map(str, digits(n, 3)[1:][::-1])), 3)

%o def a038502(n):

%o f=factorint(n)

%o return 1 if n==1 else reduce(mul, [1 if i==3 else i**f[i] for i in f])

%o def a038500(n): return n/a038502(n)

%o def a263273(n): return 0 if n==0 else a030102(a038502(n))*a038500(n)

%o def a(n): return a263273(2*n + 1) # _Indranil Ghosh_, May 22 2017

%Y Cf. A263273, A264984, A264985.

%K nonn,base

%O 0,2

%A _Antti Karttunen_, Dec 05 2015

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Last modified March 28 09:04 EDT 2024. Contains 371240 sequences. (Running on oeis4.)